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15 March 2017, Volume 38 Issue 3 Previous Issue    Next Issue
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Information & Control

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Robust Visual Tracking with Distribution Fields Feature Selection Based on Online Discrimination GUO Qiang， WU Cheng-dong， ZHAO Ying-chun 2017, 38 (3):  305-309.  DOI: 10.12068/j.issn.1005-3026.2017.03.001 Abstract ( 593 )   HTML   PDF (957KB) ( 765 )   The Haar-like features used in MIL(multiple instance learning) trackers are not efficient to represent the appearances of the targets， and the noise samples are prone to be involved for classifier training phase， then drift in targets may happen. To solve these problems， an online discriminative feature selection (ODFS) tracking algorithm based on distribution fields (DFs) descriptors at instance level was proposed. Firstly， soft histogram method is manipulated to fastly approximate DFs， and the Haar-like features are replaced with the layers of DFs， which are adopted to represent appearance information. Then， supervised learning with prior information of instance labels is conducted; the ODFS algorithm is used to select the most optimal discrimination layer features， which can handle drift more effectively. The proposed tracking method are tested in benchmark dataset of a large variety of scenarios and under new evaluation indexes. Experimental results show the effectiveness of the algorithm. References | Related Articles | Metrics

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Face Recognition Based on Multi-feature Optimization Fusion of LBP， LPQ and Gabor with Multi-scale Blocks JIA Ming-xing， DU Jun-qiang， SONG Peng-fei， TIAN Shu 2017, 38 (3):  310-314.  DOI: 10.12068/j.issn.1005-3026.2017.03.002 Abstract ( 763 )   HTML   PDF (1176KB) ( 1072 )   There is still a problem of low recognition rate in face recognition when dealing with complex situations such as illumination， pose and facial expression， so a face recognition method based on multi-feature optimization fusion with multi-scale blocks was proposed. Three complementary characters were considered as the features needed， such as local binary pattern(LBP)， the local phase quantization(LPQ) and wavelet transform. Further， a method of multi-scale blocks of face grayscale image was proposed to consider that the single block algorithm made the surrounding information not be fully extracted and thereby lost useful features for face recognition. Finally， genetic algorithm was used to optimize the weights of multi-feature of multi-scale blocks， and the optimal weights could be obtained. Experiment 4 with this method was tested on the basis of large scale face data set FRGC2.0 database， and the validation rate of the method reached 95.31%， with recognition rate reaching 99.06%. Compared to the previous literature， this algorithm can extract more feature information of human face， and improve the face recognition rate. References | Related Articles | Metrics

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Rapid Retrieval Technology of Query by Humming Based on Sentence Features WANG Pei-pei， YANG Xiao-chun， WANG Bin， WANG Xiao-ye 2017, 38 (3):  315-319.  DOI: 10.12068/j.issn.1005-3026.2017.03.003 Abstract ( 623 )   HTML   PDF (620KB) ( 915 )   As an important way of music retrieval， query by humming has gained wide attention because of its effectiveness and convenience. A novel retrieval technology of humming was proposed based on sentence features， which could provide fast retrieval for query by humming. In the proposed technology， the music database and humming given by users were first partitioned according to natural pauses， and then the BDTW (bounded dynamic time warping) algorithm was adopted to compute pitch similarity. In addition， users can also establish personalized settings in accordance with their own humming， and limit the maximum local length variance between music database fragments and query sequences. In addition， the index structure DIS was established to support music sentence query， which could reduce searching time. The experimental results verified both the efficiency and effectiveness of the proposed retrieval method. References | Related Articles | Metrics

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Power and Bandwidth Joint Allocation Method for LEO Satellites XU Shuang， WANG Xing-wei， HUANG Min 2017, 38 (3):  320-325.  DOI: 10.12068/j.issn.1005-3026.2017.03.004 Abstract ( 795 )   HTML   PDF (497KB) ( 971 )   Onboard power and bandwidth of low earth orbit (LEO) satellite networks are limited， thus designing an efficient resource allocation method is of great significance. A power and bandwidth joint allocation method for LEO satellites was proposed， and improved the resource allocation fairness among satellites and network service carrying ability were improved. The ground stations number and user data links life time were used to describe proportional constraints of intersatellite links capacity， and satellite resources allocation problem was formulated as a nonlinear mixed integer programming problem. Swallow swarm optimization (SSO) was improved by introducing dynamic feasible region and defining binary variable update operation， then the optimization model was solved by using this method. Simulations demonstrate satellite instantaneous throughput capacity and network instantaneous capacity change periodically with random fluctuations. The method achieves the resource allocation fairness among satellites at cost of network capacity. References | Related Articles | Metrics

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An Intelligent Fault-Tolerant QoS Routing Mechanism Based on PSO and SA Hybrid Optimization ZHANG Qing-yi， WANG Xing-wei， HUANG Min 2017, 38 (3):  325-330.  DOI: 10.12068/j.issn.1005-3026.2017.03.005 Abstract ( 527 )   HTML   PDF (544KB) ( 848 )   Network is vulnerable when failures happen due to its heterogeneity， mobility and instability， at the same time reliability and user QoS(quality of service)cannot be guaranteed. Therefore fault tolerance needs to be improved to guarantee the reliability of QoS routing. For this purpose， an intelligent fault-tolerant QoS routing mechanism was proposed based on PSO(particle swarm optimization)and SA(simulated annealing). Considering the network dynamics， network model was quantitatively described by introducing knowledge of fuzzy mathematics and probability theory. The SRLG(shared risk link group)disjoint and preventive shared-path protective strategy were adopted to find backup path， which optimized end-to-end reliability， cost and QoS parameters. Simulation results indicate that the proposed mechanism has good performance on the percentage of route validity， fault-restoring ratio and resource utilization and thus is feasible and effective. References | Related Articles | Metrics

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Beacon Transmission Power Control Algorithm Based on the Preset Threshold in VANETs MO Yuan-fu， YU De-xin， BAO Sai-nan， GAO Shu-tao 2017, 38 (3):  331-334.  DOI: 10.12068/j.issn.1005-3026.2017.03.006 Abstract ( 609 )   HTML   PDF (343KB) ( 762 )   Beacon transmission power control algorithm based on the preset threshold was put forward in vehicle ad-hoc networks (VANETs). First， according to the preset channel load threshold， a reasonable channel load interval is adjusted to ensure that all the nodes transmit beacon messages. Based on the beacon transmission power of all the vehicles in the carrier sensing range of the target node， the channel load is controlled within a certain range to avoid channel congestion. Then， by simulating the basic sections of eight-lane highways and actual road driving tests， the beacon transmission power control algorithm based on the preset threshold is verified with the correlation analysis. The experimental results show that this power control algorithm can effectively control channel load， avoid channel congestion， and enhance the stability and robustness of wireless beacon message transmission in VANETs. References | Related Articles | Metrics

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Efficient Traffic-Aware Routing Scheme for Software Defined Networks ZHU Lie-huang， ZHANG Qiong-yu， SHEN Meng， WANG Ming-zhong 2017, 38 (3):  335-340.  DOI: 10.12068/j.issn.1005-3026.2017.03.007 Abstract ( 667 )   HTML   PDF (705KB) ( 985 )   Routing decision in software defined networks (SDN)， which was based on the shortest path model， was unable to guarantee to minimize the delivery delay in the routing path. An efficient traffic-aware routing scheme was proposed， in which the information delivery latency was taken as the measurement of the routing efficiency. Based on the network-wide traffic information， various traffic indicators were considered by this scheme， including available bandwidth， packet loss probability， delay， switches invalidity probability， and routing path length， to find out the optimal routing path to enhance the efficiency of data delivery in networks. Experiments show that the scheme outperforms current scheme applied in OpenFlow framework with up to 90% improvement on efficiency. What’s more， the scheme is helpful to maintain the load balance of the networks. References | Related Articles | Metrics

Materials & Metallurgy

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Strengthening and Toughening Mechanism of Hot-Rolled Low Carbon Vanadium Steel CUI Chen-shuo， GAO Cai-ru， SU Guan-qiao， GAO Xiu-hua 2017, 38 (3):  341-345.  DOI: 10.12068/j.issn.1005-3026.2017.03.008 Abstract ( 640 )   HTML   PDF (1940KB) ( 842 )   Composition design of low cost V-N microalloying steel was studied without adding Mo， Cr， Ni. The thermo-mechanical control process (TMCP) test was conducted. The phase transition mechanism and precipitation behavior were discussed. The microstructure and comprehensive mechanical properties of the hot-rolled Bainitic steel were systematically studied by optical microscopy， scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results indicated that the microstructure is consisted of acicular ferrite， quasi-polygonal ferrite and granular bainite and small triangular M/A island. The fine precipitates present disks and distribute dispersedly in the ferrite matrix. The yield strength， tensile strength and elongation of the steel are 618MPa， 701MPa and 19%， respectively. The property of cold bending is qualified， the hold-expansion ratio reaches 94%， and strentch-flangeability and the low temperature impact performance is good. The above results can meet the demand of the automotive wheel disc. The fine grain strengthening， solid solution strengthening， precipitation strengthening and phase transformation strengthening are the main strengthening mechanisms. References | Related Articles | Metrics

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Influence of Microstructure on the Fatigue Crack Growth in Near-α Ti Alloy BT-20 GUO Qing-qing， WANG Jia-liang， WU Yong-hong， JIANG Yong-zheng 2017, 38 (3):  345-349.  DOI: 10.12068/j.issn.1005-3026.2017.03.009 Abstract ( 647 )   HTML   PDF (2741KB) ( 1164 )   The lamellar， bimodal， acicular microstructures and grain morphology of BT-20 near-α Ti alloy were observed by optical microscopy and electron backscatter diffraction. Tensile and fatigue crack growth tests were carried out to analyze the mechanical property and the influence of microstructures on fatigue crack growth rate， path and fractography. The results showed that the bimodal microstructure has the highest strength and best ductility， and acicular microstructure exhibits the lowest strength and poor ductility. The fractography of bimodal microstructure is cleavage fracture. The transgranular fracture happens when crack encounters the large primary α grain， which results in a relatively straight profile of the crack and explains the higher crack growth rate. The fractography of the lamellar and acicular microstructures is intergranular fracture. The crack path changes direction when encounters boundaries of two colonies of α grains， which results in tortuosity of the crack， lower crack growth rate and a better crack growth resistance. References | Related Articles | Metrics

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Brittle Fracture Mechanism and Impact Energy Scattering of Quenched and Tempered 07MnNiMoDR Steel SHI Kun， HOU Hong， LI Jin-fu， ZHANG Han-qian 2017, 38 (3):  350-355.  DOI: 10.12068/j.issn.1005-3026.2017.03.010 Abstract ( 659 )   HTML   PDF (3316KB) ( 815 )   The impact energy of quenched and tempered (Q&T) 07MnNiMoDR steel was measured. The brittle fracture micro-mechanism in the ductile-brittle transition temperature (DBTT) region was studied. The results showed that the brittle fracture behavior is controlled by bainitic packets size. A critical packet size exists. When a micro-crack formed in the bainitic packet with a size exceeding the critical size propagates into adjacent packets under normal stress， brittle cleavage fracture occurs. The discrete distribution of the coarse bainitic packets leads to the scatter of brittle fracture load， which results in the impact energy scattering. It is suggested that homogenizing the distribution of fine bainitic packet sizes is an effective method of improving the impact energy and reducing its scattering in the DBTT region. References | Related Articles | Metrics

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Test and Evaluation of Dust Emissions During Sintering Process in an Iron and Steel Enterprise ZHAO Liang， LI Xiao-ling， ZHANG Ge， SUN Wen-qiang 2017, 38 (3):  356-360.  DOI: 10.12068/j.issn.1005-3026.2017.03.011 Abstract ( 552 )   HTML   PDF (704KB) ( 843 )   The particulate matter size distribution and chemical element of particles both emitted and collected by precipitators from different processes， including coal broken， ingredient， sintering machine head， sintering machine tail and product screening of sintering process，were measured in site of an iron and steel enterprise. Based on the test results， the comprehensive evaluation index in each dust emission point of the sintering process were established. The weight of each evaluation index was obtained from experts. Then， each dust emission point was evaluated by the method of fuzzy comprehensive evaluation. The results showed that the sintering machine head is the most important dust emission point with the most emission quantity and the highest mass fraction of PM2.5， PM10 and heavy metals. References | Related Articles | Metrics

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Motor Power Model of Cold Rolling Based on Numerical Integration and Power Loss Test CHEN Shu-zong， LI Xu， PENG Wen， ZHANG Dian-hua 2017, 38 (3):  361-365.  DOI: 10.12068/j.issn.1005-3026.2017.03.012 Abstract ( 583 )   HTML   PDF (845KB) ( 829 )   A new online motor power model was put forward to improve the motor power calculation accuracy. In the model， the motor power was divided into two parts: rolling power and mechanical power loss. The rolling power was calculated by the simple finite element numerical integration method， and the mechanical power loss of the motor was obtained through field test and the regression method. Based on the proposed test scheme and model structure， the coefficients of the power loss model were obtained by using the actual test data of a 1450mm 5- stand tandem cold mill. The proposed power model was applied to the 5-stand tandem cold mill. The application results showed that this model is accurate and the relative error of motor power prediction is within ±5%， which can meet the requirement of online process control and has a good application prospect. References | Related Articles | Metrics

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Prediction Method of Rough Rolling Thickness Based on the Soft Sensor Model PENG Wen， MA Geng-sheng， GONG Dian-yao， ZHANG Dian-hua 2017, 38 (3):  366-369.  DOI: 10.12068/j.issn.1005-3026.2017.03.013 Abstract ( 671 )   HTML   PDF (507KB) ( 685 )   In order to improve the thickness control precision and meet the demand of the pass dynamic correction in rough rolling process， a simple and effective thickness soft sensor model was proposed. The study of rolling tracking and data processing was carried out based on the instrument arrangement in typical rough rolling. The strategy of gradual vertical roll-gap was proposed to measure the width in the even pass. And the thickness of each pass was obtained by the soft sensor model. The application results showed that the thickness is in a good agreement with the actual measured ones. The predicted precision error in the range of ±0.10mm reaches 95.2%， which can meet the demand of the production. References | Related Articles | Metrics

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Preparing and Characterization for Caustic Calcined Magnesite and Its Effect on Quality of Green-Pellets GAO Qiang-jian， JIANG Xin， SHEN Feng-man， LIU Chang-sheng 2017, 38 (3):  370-374.  DOI: 10.12068/j.issn.1005-3026.2017.03.014 Abstract ( 597 )   HTML   PDF (813KB) ( 710 )   Caustic calcined magnesite was utilized as an additive for pellets. The charterers of caustic calcined magnesite and the effects of activity on the quality of green-pellets were analyzed when the magnesite was calcined in different conditions. The results showed that when the calcined temperature is lower or the calcined time is inadequate， the decomposition of magnesite is limited and the hydration activity is lower， while the calcined temperature is much higher or the calcined time is much longer， the activity is destroyed. In 800~850℃， the caustic calcined magnesite has good characteristics such as high hydration activity， small granularity， large specific surface area and small average diameter of crystal grain. Caustic calcined magnesite with high activity can improve the dropped strength (DS/Times) and compressive strength of green-pellet(CSGP/N)， and can enhance the burst temperature of green-pellet(tb/℃)， especially， the burst temperature(tb/℃)can be increased up to 150℃. References | Related Articles | Metrics

Mechanical Engineering

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Residual Strength of Notched Fiber Metal Laminates TONG An-shi， XIE Li-yang， LIU Jian-zhong， ZHANG Xiao-chen 2017, 38 (3):  375-378.  DOI: 10.12068/j.issn.1005-3026.2017.03.015 Abstract ( 492 )   HTML   PDF (412KB) ( 753 )   Fiber metal laminates (FMLs) are a family of hybrid materials consisting of alternating thin coatings of aluminum alloy and fiber-reinforced epoxy layers. In contrast to aluminum alloys， the presence of notches in FMLs causes significant strength reduction. To evaluate the residual strength of fiber metal laminates with circular open hole， mechanical testing was performed to determine the un-notched tensile properties and notched strength of FMLs. The influence of ply structure on residual strength of FMLs was investigated. The stress failure model was introduced to predict the residual strength of FMLs with an open hole. Failure modes， damage initiation and progression of notched FMLs were also characterized and discussed. The results show that the presence of a hole in GLARE3 laminates gives a strength reduction about 40%. It can be seen that the characteristic length increase and notch sensitivity tends to decrease with the increase of ply number. The damage initiated at the hole edge when the residual strength is 90%. References | Related Articles | Metrics

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Roll Forming Process Design of Corrugated Structure of Heat Exchanger Plate JIA Wei-tao， MA Li-feng， LE Qi-chi 2017, 38 (3):  379-384.  DOI: 10.12068/j.issn.1005-3026.2017.03.016 Abstract ( 658 )   HTML   PDF (758KB) ( 996 )   The shape parameter of stainless-steel heat exchanger plate is complex. Considering that the traditional stamping preparation process has a low efficiency， a roll forming process combined with stamping process was put forward. According to the bending theory of the stamping process and cold-bending formation process， mathematical models of rolling parameters about the corrugated structure were established and further optimized. The results show that the corrugated structure of heat exchanger can be formed by single-pass rolling process with a high preparation efficiency. Through the quantitative study of the deformation resilience， the processing accuracy of the physical parameters of the plate is basically satisfied with the technical standard. References | Related Articles | Metrics

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Experiment on Surface Quality in Micro-milling of Single Crystal Ni-Based Superalloy DD98 GAO Qi， GONG Ya-dong， ZHOU Yun-guang， WEN Xue-long 2017, 38 (3):  385-389.  DOI: 10.12068/j.issn.1005-3026.2017.03.017 Abstract ( 706 )   HTML   PDF (2030KB) ( 742 )   To study the micro-milling surface quality of single crystal superalloy， orthogonal experiment was implemented for micro-milling of single crystal Ni-based superalloy DD98 by using the M.A.FORD two-edged micro-milling tool with 0.8mm diameter. The primary and secondary impacting factors on the micro-milling surface quality， such as spindle speed， feed rate and milling depth were analyzed by range analysis. The results show that the influence of spindle speed is the greatest， the milling depth is the secondary， while the feed rate is the smallest. Using statistical theory， the ideal cutting process parameters was optimized and obtained， i.e， 3.6kr/min speed spindle， 5μm milling depth and 100μm/s feed rate. The surface roughness is minimum under the above combination condition. The experiments were repeatedly done with the optimized scheme to get a surface roughness (Ra) of 951nm. The cutting mechanism， the reasons of affecting surface quality and morphology were further analyzed. The experiment result may provide some reference for micro-milling mechanism of single crystal superalloy. References | Related Articles | Metrics

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Study on Improving the Machining Accuracy of Aviatic Thin-Walled Parts with the Adjustable Airbag LIN Wen-qiang， JIAO Ming-yu， ZHAO Xi-song， YU Xian-yong 2017, 38 (3):  390-394.  DOI: 10.12068/j.issn.1005-3026.2017.03.018 Abstract ( 571 )   HTML   PDF (2340KB) ( 762 )   Taking the front casing as typical part， the adjustable pressure airbag was proposed to improve the machining accuracy of aviatic thin-walled parts. The orthogonal analysis method was adopted in the system to carry out the finite element simulation in thin-walled cutting， the cutting deformation under different work parameters was analyzed， and then the deformation trend of the cutting point changing with work parameters was studied. Thereby， the work parameters were optimized in thin-walled parts. As a result， the error caused by work parameters was reduced by more than 60%， which could directly provide guidance on the processing of thin-walled parts. On the basis of optimized work parameters， an adjustable pressure airbag was taken as the support. Using different pressure airbags according to the deformation of cutting points， the clamping deformation can be reduced by more than 40% on the basis of optimization， which will reduce the part deflection and control the machining precision of thin-walled parts. References | Related Articles | Metrics

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Surface Grinding Hardness Layer Thickness Prediction Under Pre-stress Loading Condition MA Liang， DONG Le， ZHANG Xiu-ming， XIU Shi-chao 2017, 38 (3):  395-399.  DOI: 10.12068/j.issn.1005-3026.2017.03.019 Abstract ( 552 )   HTML   PDF (819KB) ( 739 )   To evaluate the effect of pre-stress parameter on hardening-layer thickness during grinding process， surface grinding hardening process was applied to unquenched 45# steel workpiece at different pre-stress (0~100MPa) conditions. In a sequence of “thermal-force” loading order， grinding hardening process was simulated using the ANSYS software. Furthermore， how thermal transformation and work hardening influence layer thickness and thickness distribution at different location from grinding wheel’s entry point were discussed. Thickness simulation data shows that the calculation error is less than 6%， indicating that the results are in good agreement with the experimental data. Meanwhile， the pre-stress loading leads to the slight reduction of thickness (<10%) on the surface grinding hardening-layer， which proves that loading pre-stress provokes re-distribution of microstructure， suppresses diffusion of quenched carbide， but probably is not a beneficial factor to increase hardening layer thickness. References | Related Articles | Metrics

Resources & Civil Engineering

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Experiment of Recovery Method for Ore Overburden in Sublevel Caving LEI Gang， LI Yuan-hui， ZHANG Zhi-gui， LI Rui 2017, 38 (3):  400-405.  DOI: 10.12068/j.issn.1005-3026.2017.03.020 Abstract ( 656 )   HTML   PDF (1831KB) ( 816 )   Pangang Lanjian Iron Mine used sublevel caving method after open-pit turned to underground mining. In order to ensure the safety of mining in lower segment， around 40m ore overburden had been set aside at the top segment. To explore the best way to recover ore overburden that had reserved in the stope， similar physical simulation experiment which includes the way of no dilution drawing， low dilution drawing， cut-off grade drawing and step away from the collapse of the amount of ore to 100% was designed in laboratory. Through the comparative analysis of recovery rate， dilute rate and the integrity of ore rock interface， it is concluded that the use of no dilution drawing method in sublevel caving generates the best economic benefit， which provides reference for similar mines about recovery method of ore overburden. References | Related Articles | Metrics

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Experiment of Resisting Shear and Compression Index of Silt Corroded by Hydrochloric Acid Solution WANG Shu-hong， BAI Long-fei， HAN Li， WANG Cun-gen 2017, 38 (3):  405-409.  DOI: 10.12068/j.issn.1005-3026.2017.03.021 Abstract ( 580 )   HTML   PDF (688KB) ( 653 )   The composition， microstructure and mechanical indexes of the soil can be changed by acid solution. Through the 0 (water)，1%，4%，8%，12% concentration of hydrochloric acid solution soak tests， the silt polluted by acid solution was simulated. The variability of resisting shear and compression index about the corroded silt was gained by indoor consolidated quick shear test and quick consolidation test. The results show that the cohesive force is increased， the internal friction angle and the compression modulus are decreased， and the compression coefficient and the compression index are increased. The reason for the corroded silt property variation about material composition and microstructure was explained by the results of the chemical composition analysis and scanning electron microscope. The relevant indexes of bearing capacity and slop stability will be changed consequentially because of the variations about resisting shear and compression ability. Therefore， the above variable conditions should be considered in the survey design and analysis of the accident causes for the silt region with acid pollution hazard. References | Related Articles | Metrics

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Relationship Between China’s Iron Ore Intensity of Use and the Iron and Steel Smelting and Rolling Industries GU Xiao-wei， QIN Zong-chen， WANG Qing， WANG Feng-bo 2017, 38 (3):  410-413.  DOI: 10.12068/j.issn.1005-3026.2017.03.022 Abstract ( 565 )   HTML   PDF (376KB) ( 724 )   China’s iron ore intensity of use was analyzed for its changing characteristics in different periods since the adoption of reform and opening-up policy. An increments decomposition model was developed for the iron ore intensity of use. The increments in iron ore intensity of use in different periods were decomposed and analyzed using the value added and total output data from China’s input-output tables. The results showed that before 2002， the growth rate of capital formation was either lower than or almost equal to that of GDP， and the ISSRI’s iron ore consumption factor decreased to drive down the iron ore intensity of use. From 2002 to 2010， the growth rate of capital formation was higher than that of GDP， and the ISSRI’s output efficiency went down while its iron ore consumption factor went up significantly， resulting in a sharp rise of the iron ore consumption intensity. Accordingly， the main problem to be solved for ISSRI is to eliminate surplus capacity of low-value products and upgrade its product structure so that the iron ore intensity of use in the economic system can be lowered， achieving the goal of sustainable and healthy industrial development. References | Related Articles | Metrics

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Analysis of Risk Coupling of Gas Explosion Accidents ZHANG Jin-jia， XU Kai-li， WANG Yan-tong， WANG Ben 2017, 38 (3):  414-418.  DOI: 10.12068/j.issn.1005-3026.2017.03.023 Abstract ( 652 )   HTML   PDF (482KB) ( 976 )   The connotation and types of risk coupling of gas explosion accidents were defined on the physics， synergetics and catastrophology concepts. Moreover， hierarchical network model of risk coupling of gas explosion accidents was constructed from the perspective of risk emergence for a complex system. Then， coupled correlation of risk factors was analysed by using the N-K model. The result shows that gas explosion accidents are the consequence of stepping mutation from the nonlinear coupling between micro risk factors to macro hierarchical structural state， and the more the number of coupled risk factors is， the easier the gas explosion accidents are triggered. In the control process of risk coupling， risk coupling of objective factors is more difficultly controlled than that of the subjective factors. References | Related Articles | Metrics

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Constitutive Model of Shenyang Medium-Coarse Sand Based on Disturbance Theory CHEN Chen， ZHAO Wen， LIU Bo， JIA Peng-jiao 2017, 38 (3):  418-423.  DOI: 10.12068/j.issn.1005-3026.2017.03.024 Abstract ( 557 )   HTML   PDF (646KB) ( 771 )   The results of triaxial consolidation drained shear tests on medium-coarse sand in Shenyang region under different confining pressures show that the relative density strongly affects the strength-deformation property of medium-coarse sand.Taking the relative density as independent variables， the general disturbance function was put forward. Then the modified D-C model， which could reflect the disturbance’s influence on the strength-deformation property of medium-coarse sand， was developed by establishing the relationship between parameters K and peak strength and disturbed degree. The contrasts of the forecast results between the modified D-C model and D-C model are as follow: the forecast results of D-C model and experimental results are consistent when D○D is close to zero; the stress value predicted by D-C model is larger than the modified model in this paper when sand is positive disturbance; the stress value predicted by D-C model is smaller than the correction model when sand is negative disturbance. It is found that the modified D-C model can describe the strength-deformation property of medium-coarse sand better than D-C model at the disturbed state. References | Related Articles | Metrics

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Comparative Study on Geotechnical Properties of Soft Soils Considering Depositional Environment WU Chang-sheng ， ZHU Zhi-duo 2017, 38 (3):  424-429.  DOI: 10.12068/j.issn.1005-3026.2017.03.025 Abstract ( 556 )   HTML   PDF (712KB) ( 742 )   Typical soft soils from Lian-Yan Expressway (Lianyungang section) and Hu-Su-Zhe Expressway (Suzhou section) were selected to study the geotechnical properties through general indexes and specific sections indexes considering depositional environment， respectively. The effects of depositional environment， clay fraction， clay minerals， and pH values on geotechnical properties of soft soils in LY and HSZ were discussed. The research results are as follows: Lianyungang marine clay gradually deposits with the sea level change in alkaline condition. Its material sources derives from marine sediments. Clay fraction is dominant and the principal clay mineral of the soils is illite-smectite mixed-layer mineral. Differing from the Lianyungang marine clay， Suzhou lacustrine soft soil gradually deposits in neutral condition and weak alkaline condition. Its material sources derives from Maoshan and Tianmushan. Silt fraction is dominant and the principal clay mineral of the soils is illite. Water content is lower while the unconfined compressive strength and sensitivity are higher than that of Lianyungang marine clay. References | Related Articles | Metrics

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Hysteretic Behavior of Semi-rigid Space Steel Beam-to-Column Joints with Channel Components CAI Yong， LYU Xiao-yong， YANG Wen-chao， LI Zhe 2017, 38 (3):  430-435.  DOI: 10.12068/j.issn.1005-3026.2017.03.026 Abstract ( 636 )   HTML   PDF (668KB) ( 681 )   Semi-rigid space end-plate connections of weak-axis with channel components are new end-plate connections form. The finite element analysis of semi-rigid space beam-to-column joints with channel components under cyclic loading was carried out in order to investigate its seismic performance， and the mechanical characteristics， joint stiffness and energy dissipation capacity of weak-axis joints under cyclic loading were analyzed when its strong-axis joint was yielded under the static load. The results showed that the weak-axis joint with channel components has a good energy dissipation capacity， and the loading of strong-axis has almost no effect on the weak-axis connections’ capacity property but exerts some effect on the weak-axis connections’ hysteretic behavior. In accordance with the results of the finite element analysis， the curvilinear hysteretic model expression of weak-axis joints with channel components was modified， which may provide reference for practical projects. References | Related Articles | Metrics

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Adaptability of Roadway Section Shape in Deep Inclined Seam CAO Shu-gang， WANG Shuai， WANG Shou-quan， YANG Hong-yun 2017, 38 (3):  436-441.  DOI: 10.12068/j.issn.1005-3026.2017.03.027 Abstract ( 547 )   HTML   PDF (1945KB) ( 709 )   Based on distribution of surrounding rock stress in deep inclined seam roadway，the asymmetric distribution law of the plastic zone and stress of different cross-section roadway were studied by using numerical method， and a mechanical model of special-section roadway was established to determine the reasonable support mode. The results show that deep inclined seam roadway plastic zones extend along the dip direction of coal seam，failure of roof and floor is greater than that of ribs， and what is more， different damage and failure occur in ribs; the roadway shape affects the stress concentration， plastic zone and deformation; arched roadway adapts well， and special-shaped tunnel is likely to lead to shear failure-prone in the roof side corner， but taking roadway service life and mining issues into account， special-shaped tunnel can meet the requirements under the existing support conditions. The combination supports of “anchor net + steel band + anchor rope” are adopted to strengthen the rib beside roof and the roof coal for special-shaped tunnel， and the support stress should be above F○1and F○2. By this way， surrounding rock deformation is obviously reduced and the roadway can stay stable. References | Related Articles | Metrics

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Flexural Performance of Textile Reinforced Self-Stressing Concrete Beam WANG Bo-xin， ZHAO Jian-yu， WANG Qing 2017, 38 (3):  442-447.  DOI: 10.12068/j.issn.1005-3026.2017.03.028 Abstract ( 515 )   HTML   PDF (1599KB) ( 711 )   According to ASTMC1018—97 the test was carried out to study the flexural toughness of textile reinforced self-stressing concrete (TRSSC) beam. The load-deflection curves were obtained， which are affected by the different kinds of matrix and the content of Tex in fibrous bundle. The results show that the cracking load of self-stressing concrete beams is improved markedly owing to the textile and increase of Tex. However， with the increase cracking load， the flexural toughness index I5，I10 and I○20of TRSSC decreased gradually. Meanwhile， a theoretical model of determining the cracking load was established and a computer analysis was given in this paper. The calculation results are in agreement with the experimental results， which indicates that the theoretical model can evaluate the crack resistance of TRSSC beam. References | Related Articles | Metrics

Management Science

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Working Mechanism Between Emotional Labor and Organizational Citizenship Behavior: From the Service Climate Perspective ZOU Zhen-dong， YANG Yong， WANG Hui， MA Qin-hai 2017, 38 (3):  448-452.  DOI: 10.12068/j.issn.1005-3026.2017.03.029 Abstract ( 669 )   HTML   PDF (372KB) ( 812 )   In order to research how emotional labor works on organizational citizenship behavior in Chinese cultural context， the data of 312 staff were obtained through multi-time investigation and then analyzed by using AMOS and SPSS statistical tools. The research results were as follows: surface acting has negative significant effect on the four dimensions of organizational citizenship behavior including individual foci citizenship behavior， group foci citizenship behavior， organizational foci citizenship behavior and social foci citizenship behavior; deep acting has positive significant effect on the four dimensions of organizational citizenship behavior; and service climate has positive moderation effect on the relationship between surface acting and group foci together with social foci organizational citizenship behavior. References | Related Articles | Metrics

Mathematics

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Modified SOR-Like Method for Saddle Point Problems SHAO Xin-hui， LI Chen， WANG Xin-yi 2017, 38 (3):  452-456.  DOI: 10.12068/j.issn.1005-3026.2017.03.030 Abstract ( 515 )   HTML   PDF (344KB) ( 674 )   Saddle point problems exist in many engineering research areas such as fluid mechanics， electromagnetism， optimization problems， the least squares problems， elliptic partial differential equations， and etc. Based on SOR-Like methods in combination of the concept of HS splitting， a new iteration splitting improvement method was presented so as to apply the classic saddle point solutions to special saddle point problems. Then， the MSOR-Like method was proposed to handle the above special saddle point system containing asymmetric blocks， and the convergence analysis as well as the selection of optimal relaxation parameters were also given. Finally， a numerical example was given to verify different optimal matrix of the modified SOR method， and it was found that the only difference is in the convergence rate while there is no difference in the convergence effect. Furthermore， under the same calculation accuracy， the modified SOR method for solving the special saddle point problems is better than the conventional methods in solving the classical saddle point problems. References | Related Articles | Metrics